Jake, thanks for starting this thread. Lantern pronunciation is a contested area and is often discussed in person but rarely on the forums and if so, on an ad hoc basis. So this thread is a great idea!
I believe I've discussed with both member Inkubate and Mike Barford the pronunciation of Metal Halide. I've always pronounced it as "Metal Ha-lid" whereas they both pronounce it as "Metal Hay-lied." We also discussed the pronunciation of cosmopolis; inkubate favours "cos-MOP-olis" whereas Mike and I favour "cosmo-POLIS".
I says SOX and GEC as "socks" and "geck" respectively, but I wonder who says them as "ess oh ex" and "gee ee see"?
How do people pronounce Phosco and ELECO? I say "Pho-so" (to rhyme with photo) but I think I've heard "phos-ko" before. I used to say "Eleck-oh" but I've changed my ways and now say "il-eek-oh"
Urbis 'Opalo' (perhaps Oh-pa-low, Oh-par-low, or 'Apollo'?)I'm not certain about this one, but I say "Oh-pa-low".
Philips 'Iridium' (I as in investigate or I as in WiFi?)It is "Ih-RID-ium" with stress on the second syllable. I as in investigate.
Holophane 'Syracuse' (I'm not even going to attempt to pronounce this one...)I say "sy-ra-queues"